ML20235Q093

Responds to Generic Ltr 88-14, Instrument Air Supply Sys Problems Affecting Safety-Related Equipment. During 1989 Refueling Outage,Instrument Air Sys Will Be Removed from Svc for Maint & Air Dryer Replacement

ML20235Q093
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	02/20/1989
From:	Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-88-14, NUDOCS 8903020492
Download: ML20235Q093 (14)

Text

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Consumers Power Kenneth W Berry MM Director

_ gmg Nuclear Licensing General Offices: 1945 West ParneN Road, Jackson, MI 49201 (517) 788 1636 February 20, 1989 ,

Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -

INSTRUMENT AIR SUPPLY SYSTEM PROBLEMS AFFECTING SAFETY-RELATED EQUIPMENT -

RESPONSE TO GENERIC LETTER 88-14 Generic Letter 88-14 related concerns associated with instrument air systems and requested each licensee review NUREG-1275, Volume 2, and perform certain actions to verify design and operation of its instrument air system. This letter provides Consumers Power Company's initial response for Big Rock Point Plant. Actions completed to date have not identified any components that cannot perform their intended safety function because of instrument air system ,

deficiencies.

As allowed by Generic Letter 88-14, and as indicated in this response, some actions requested will not be completed within 180 days of the letter.

Consistent with the plan for the Big Rock Point Integrated Assessment, specified in the Facility Operating License, Big Rock Point's Technical Review Group (TRG) has reviewed the remaining actions and, based on the results of the completed design verification and previously planned modifications to improve air system reliability has added this item to the Big Rock Point Integrated Plan as Issue BN-130, with completion scheduled for December 31, 1990. The planned modifications are a result of completion of Integrated Plan Issue B-126, " Station Air Compressor", which consisted of a study of the entire air system and was active at the time the generic letter was received. Integrated j Plan Semi-annual Update, Number 9, submitted September 26, 1988, stated that '

issue B-126A, " Station Air System Upgrade," was being added, and described l some of the modifications to be made. Issue B-127, " Replace Instrument Air i Dryer", was also included, with an identified completion date of the 1989 1 refueling outage. Thus, it is appropriate to schedule completion of remaining i GL 88-14 actions to occur after the planned modifications are in service.

While this takes completion of some actions beyond the "next scheduled outage,"

as required by GL 88-14, Consumers Power Company believes this is justified 8903020492 890220 PDR ADOCK 05000155 P PDC OC0269-0049-NLO2 l okd I\

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Nuclear Regulatory Commission 2 Big Rock Point Plant

" Response to GL 88-14 j February 20, 1989 based on the information supplied in the attached response, including the facts that, 1) there have been no recent instrument air quality problems, 2) all safety-related equipment supplied from instrument air is designed to perform its intended safety function on loss of air (ie, the instrument air system is not " safety-related"), and 3) the previously planned modifications to the air system will improve both the air system reliability and the ability to monitor system performance and conduct the recommended tests.

In accordance with the provisions of 10 CFR 50.54(f), this response is submitted under oath and affirmation. 1 I

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'l{g, ,92 ) ' V i

Kenneth W Berry Director, Nuclear Licensing CC Administrator, Region III, NRC NRC Resident Inspector - Big Rock Point ,

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CONSUMERS POWER COMPANY Big Rock Point Plant Docket 50-155 License DPR-6 Response to Generic Letter No 88-14 dated August 8, 1988 At the request of the Commission and pursuant to the Atomic Energy Act of 1954 and the Energy Reorganization Act of 1974, as amended, and the Commission's Rules and Regulations thereunder, Consumers Power Company submits our response to NRC letter dated August 8, 1988, entitled, " Instrument Air Supply Problems Affecting Safety-Related Equipment." Consumers Power Company's response is dated February 20', 1989.

CONSUMERS POWER COMPANY N

By -

DavidPHoffmda/QipePresideW Nuclear Operations Sworn and subscribed to before me this 20th day of February, 1989.

LL Elaine E Buehrer', Notary Public Jackson County, Michigan My commission expires October 31, 1989 ,

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ATTACHMENT 1 Consumers Power Company Big Rock Point Plant Docket 50-155 RESPONSE TO GENERIC LETTER 88-14 INSTRUMENT AIR SYSTEM PROBLEMS AFFECTING SAFETY-RELATED EQUIPMENT February 20, 1989 l

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l Generic Letter 88-14 requested each licensee / applicant perform several actions ]

related to instrument air systems. Specifically, GL 88-14 stated: l "The purpose of this generic letter is to request that each licensee /

applicant review NUREG-1275, Volume 2, and perform a design and operations verification of the instrument air system."

l l Big Roch Point has completed the required review of NUREG-1275, Volume 2, as requested. The generic letter goes on to state:

"This verification should include:

1. Verification by test that actual instrument air quality is consistent with the manufacturer's recommendations for individual components served."

Status Significant difficulty has been encountered both in identifying " manufacturer's recommendations" regarding the specific characteristics that make instrument air quality acceptable for their individual components, and in compilation and development of detailed system drawings / sketches to accurately depict the instrument air piping / equipment configuration due to inaccessibility of certain plant areas during plant operation. Neither action had been done in the past because the Big Rock Point instrument air system is designed so that its operation is required for plant reliability, not plant safety. Any safety-related equipment supplied by instrument air is designed to fail in its safe condition on loss of instrument air.

Safety-related equipment required to operate subsequent to Instrument Air failure is supplied by backup nitrogen accumulators. Instrument air quality for most equipment is determined to be more than adequate by virtue of the system's design, which uses " oil-less" air compressors, aftercoolers, moisture separators, receiver tanks, drain traps, and an instrument air dryer. Equipment suspected of requiring a higher degree of air quality is provided with local filtering. Twenty-seven years of satisf actory performance provide further evidence that the instrument air system has functioned as designed. Detailed instrument air system inform-ation should be completed by December 31, 1989. In no case has it been {

shown that current instrument air quality levels would cause any safety-related component to be unable to perform its intended safety function.

Testing of actual air quality, either system-wide or at individual components, has not been completed. This is because: 1) a plant shutdown in required to perform much of the testing, and 2) prior to receipt of the generic letter, Big Rock Point had already planned to make certain air system modifications to improve system reliability and to provide better monitoring capability. These modifications were not due to any concerns with the safety-related equipment supplied by instrument air, but rather, dealt with total system capacity, instrument dew point, and overall air quality mcnitoring.

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i Air quality testing will be completed following installation of the I planned modifications during the 1989 refueling outage, as part'of the .l post-modification test of the new equipment; this will be in the form of a j system test. Testing of air quality at equipment locations will be.done at the'next convenient routine maintenance opportunity following completion of modifications, but not later + ben December 31, 1990. Manufacturer's specific recommendations regardirg air quality, when available, will be used as guidance in determining acceptable air quality at the component level.

"2. Verification that maintenance practices, emergency procedures, and training are adequate to ensure that safety-related equipment will function as intended on loss of instrument air."

Status Post-maintenance testing and periodic surveillance testing of safety-related equipment assures that the equipment can perform its intended safety function under design conditions, including, when applicable, loss of instrument air. Testing is governed by individual work orders and maintenance or surveillance procedures that provide the necessary verification and documentation of equipment operability prior to return to service. Big Rock Point Off Normal Procedure ONP-2.2, " Loss of Instrument Air System,"

covers symptoms and actions for dealing with loss or decaying pressure in the instrument air system. ONP-2.2 requires operators to scram the reactor when instrument air pressure cannot be maintained, and to verify that safety-related equipment functions as intended. Various other Operating Procedures, Alarm Procedures, and Emergenc) Procedures address symptoms and appropriate actions for dealing with less of, or decaying i instrument air system pressure on an individual comronet.t basis. Operators are trained in the use of these procedures.

"3. Verification that the design of the entire instrument air system including air or other pneumatic accumulators is in accordance with its intended function, including verification by test that air-operated safety-related components will perform as expected in accordance with all design-basis events, including loss of the normal instrument air system. This design verification should include an analysis of current air operated component failure positions to verify that they are correct for assuring required safety functions."

Status In 1984 an operational review of the instrument air system upon loss of air was conducted in preparation for the Refueling Outage during which the system was going to be removed from service for maintenance and modifi-cations. This review was essential to ensure that all systems function as l

intended during this mode. The results of this review were added as an OCO289-0049-NL02

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attachment to the System Operating Procedure, SOP-27, " Service and Instru-ment Air System". The results were verified during the Refueling Outage I activities and corrections / improvements were made. A copy of this inform-ation is provided as Attachment 2 to this response.

As a result of this Generic Letter, an additional review of the instrument air system design, including connected air pneumatic accumulators, has been completed. This review has concluded, by analysis, that the design is in accordance with the system's intended function.

During the 1989 Refueling Outage, the instrument air system will again be t removed from service for maintenance and air dryer replacement. Should this evolution identify any discrepancies, appropriate changes to the system operating procedures will be made.

The plant's design bases for the instrument air system has always been considered non-safety related, and safety-related components supplied from instrument air are designed so that loss of air would place it in the position needed for assuring required safety functions. This was true for the original design, as well as for subsequent modifications.  !

The generic letter also requested:

"In addition to the above, each licensee / applicant should provide a discussion of thei program for maintaining proper instrument air quality."

Discussion of Big Rock Point Program Initial Air Quality for the total air system is achieved through the system's design, i.e., through the utilization of oil-free air compressors, aftercoolers with an integral moisture separator and air receiver tanks with automatic drainer. For the instrument air portion, the air quality is further enhanced through the utilization of an instrument air dryer, designed for a -50*F pressure dew point; the dryer's associated pre-and post-filters; and various filters located at selected equipment. The pre-filter is a coalescing type 0.1 micron filter designed to remove both liquid and solid contaminants with a 99.999 percent efficiency. The post-filter is also a coalescing type 0.1 micron filter, designed to remove solid contaminants with a 93 percent efficiency.

Although a formalized air quality program has not existed, the performance of equipment determined essential to system operation and air quality (e.g., air compressor, aftercoolers, control valves, air dryer, filters, etc.) is routinely monitored by the Operations Department as part of plant rounds, such as by checks each shift for aftercooler temperature, and differential pressure levels on pre-and post-filters, and monthly loading / unloading timing check of each compressor. In addition, the plant 's preventive maintenance program covers the air system, and includes, for example, annual inspection and calibration of pressure and temperature OC0289-0049-NLO2

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l indicators on all instrument air system components, including control room {

indicators and alarms, and twice annual changeout of compressor inlet filters. This monitorfrg and preventive maintenance, in conjunction with those to be developed and incorporated subsequent to completion of planned air system modifications (e.g., Dew Point Monitoring, Particle Sampling, Hydro-carbon Sampling), will constitute Big Rock Point Plant's program to insure quality air.

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e-ATTACHMENT 2 Consumers Power Company Big Rock Point Plant Docket 50-155 SOP-27

" SERVICE AND INSTRUMENT AIR SYSTEM" February 20, 1989 5 Pages OC0289-0049-NLO2

VOLUME 3 OPERATING PROCEDURES . SYSTEM Revision 109 SOP SERVICE AND INSTRUMENT AIR SYSTEM Page 19.of 23 ATTACHMENT 1 EFFECTS ON SYSTEMS FROM LOSS OF THE INSTRUMENT AIR SYSTEM

1. Spent Fuel Pool Fuel pit filter tank level control valve CV-4128, fails closed. l

2. Reactor Clean-up Resin sluice valves CV-4091, CV-4092 and CV-4093 fail, closed.

Reactor blowdown valves CV-4040, CV-4114, fail closed.  !

Normal CU flow path valves CV-4039, CV-4042 and CV-4043, fail open.  !

3. Reactor Depressurization System Isolation valves CV-4180,'CV-4181, CV-4182 and CV-4183, remain closed if backup nitrogen supply is in service, otherwise fail they open.

Bypass isolation valve CV-4184, fails closed.

Containment evacuation alarm will sound when air is lost to the Bailey Steam Drum Level instrumentation.

4. Liquid Poison Poison tank outlet valve CV-4020, fails open.

Reactor recire pump suction CV-4050, fails closed.

5. Control Rod Drive Scram valves CV-NC09 and CV-NC10, fail open.

Scram Dump Tank valves'CV-NV11, CV-NV11A, CV-NV12 and CV-NV12A, fail closed.

Scram Damp Tank equalizing valves SV-NC14 and SV-NCIS, fail open.

Control Rod Drive condensate supply valve CV-4016, fails open.

Air operated flow control valves NC-18, fails open, NC-33, fails closed.

6. Shutdown Cooling Inhibited water and drain valves CV-4115 and CV-4116, fail closed.

RCW outlet flow control valve CV-4029, fails open.

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VOLU$E' 3 OPERATING PROCEDURES - SYSTEM Rnvisien 109

.. SOP SERVICE AND INSTRUMENT AIR-SYSTEM Page 20 of 23 ATTACHMENT'l-EFFECTS ON SYSTEMS FROM LOSS OF :

THE INSTRUMENT AIR SYSTEM

7. Emergency Condenser Demin water make-up valve CV-4028, fails closed.

8. Radwaste Reactor and fuel pit drain isolation valves CV-4027, and CV-4117, fail closed.

i Enclosure clean sump isolation valves CV-4031 and CV-4102, fail closed. l Enclosure dirty sump isolation valves CV-4025 and CV-4103, fail closed.

Radwaste sock strainer level control valve LCV-4802, fails' closed.

All Radwaste tank level indicators and recorders will be lost.

Treated waste to Canal control valves CV-4038 and CV-4126, fail closed.

Radwaste to the fuel pool and shield tank CV-4049, fails closed.

9. Ventilation The standby plant exhaust fan starts and the running plant exhaust fan stops.

Containment vent valves CV-4094, CV-4095, CV-4096 and CV-4097, remain as is, because the backup nitrogen supply takes control on decaying air pressure.

Service water to pipeway coolers CV-9459, fails open.

Ventilation air flow control dampers fail open.

Pipe Tunnel Damper CV-4190, fails closed.

Steam supply valves to heating coils fail open.

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-VOLUME 3 OPERATING PROCEDURES - SYSTEM- Rsvision 109 SOP SERVICE AND INSTRUMENT AIR SYSTEM Page 21'of 23 ATTACHMENT 1 EFFECTS ON SYSTEMS FROM LOSS OF THE INSTRUMENT AIR SYSTEM

10. Condensate and Feedwater Condenser make-up valve CV-4024, fails open.

Condenser fill valve CV-4009, fails open.

Condenser reject valve CV-4010, fails closed.

Condensate recycle valve CV-4011, fails closed.

Hotwell and condensate storage tank levels may equalize, requiring the condenser jacks to be raised.

Feedwater regulator valve CV-4000, locks in position.

11. Off-Gas Off-Gas isolation valves CV-4015, CV-4035, CV-4030, fail closed.

12. RGEM Control valves CV-4800 and CV-4802, fail open. (Normal flow path maintained.)

Purge air is lost.

13. Demin Water Make-up valve CV-4026, to RCW tank fails open. (Normally isolated.)

Demin water transfer valve CV-4041, to Condensate storage tank, fails open. ,

Demin water supply valve CV-4105, to sphere fails closed.  ;

Automatic control of make-up demin is lost. ,

14. Domestic Water Accumulator Pressure control is lost.

15. Fire Water Pressure Control on the accumulator will be lost.

Fire water supply valve CV-4101, to the substation deluge fails closed.

Fuel oil tank level indications are lost for the diesel fire pump and emergencf diesel generator.

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VOLUME 3 OPERATING PROCEDURES - SYSTEM Ravisica 109 SOP SERVICE AND INSTRUKENT AIR SYSTEM Page 22 of 23

.ATTACHKENT 1 EFFECTS ON SYSTEMS FROM LOSS OF THE INSTRUMENT AIR SYSTEM

16. Reactor Protection Pl. acing the mode switch to SHUTDOWN can eliminate the possibility of having scram valves and scran' dump tank valves open at the same time.

17. Control Room Indications Loss of the Control Room temperature / humidity control '

The following recorders will be unreliable: ,

1 LR-3100 Hotwell level j PR-50 Feed pump suction pressure PR-51 Feed pump discharge pressure LR-3104 Condensate storage tank level 1 LR-3105 Demin water tank level FR-ID07 Feedwater flow LR-ID12 Bailey steam drum level  !

FR-ID06 Steam flow l PR-IA09 Reactor pressure l The following circular gauges will be unreliable:

PI-301 Turbine inlet steam pressure PI-302 Steam seal pressure ,

PI-303 _ Steam to HP heater  !

PI-304 Steam to IP heater PI-307 Steam to LP heater

.PI-310 Condensate pump discharge j i

PI-312 First stage pressure PI-314 Condenser vacuum PI-322 Feed pump suction pressure PI-324 Bearing header oil pressure PI-327 Turbine auxiliary oil pump discharge pressure PI-328 Hydraulic oil pressure PI-352 Turbine steam bypass PI-360 Main board instrument air pressure PI-364 Plant instrument air pressure dPI-IA46A Number 1 RCP dp  ;

dPI-IA46B Number 2 RCP dp Number 1 RCP discharge flow j FI-IA44A 6 FI-IA44B Number 2 RCP discharge flow LI-IA19 West steam drum level LI-IA40 Bailey reactor water level dPI-IA41 Core dp FI-ID27 Steam flow BR0781-2035A-BA01

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. VOLUME.3 .0PERATING PROCEDURES c SYSTEM Ravision 109 SOP SERVICE AND INSTRUMENT AIR SYSTEM Page 23 of 23 ATTACHMENT 1 EFFECTS ON SYSTEMS FROM LOSS OF THE INSTRUMENT' AIR SYSTEM The following mini gauges will be unreliable:

PI-305 Number 1.feedpump discharge pressure PI-306 . Number 2 feedpump discharge pressure PI-309 Steam to air ejectors PI-323 CRD pump discharge PI-325 Demin water pump discharge pressure PI-353 - Number 1 Shutdown pump suction pressure PI-354 Number 1 Shutdown pump discharge pressure PI-355 Number 2 Shutdown pump suction pressure l PI-356 Number 2 Shutdown pump discharge pressure i PI-376- Poison system pressure

.PI-377 Poison system pressure LI-3300 IP heater LI-3302 LP heater LI-3303 HP heater LI-3305 Emergency condenser LI-3325 Moisture separator drain FI-ID53 Feedwater flow FI-2330 Feedwater low flow ,

The following alarms should annunciate on loss of header pressure:

Reactor cooling water tank level - delayed Condensate storage tank level Hi/Lo level Demin water storage tank Hi/Lo Intake structure bays low level Plant exhaust fans trouble Service air low pressbre Instrument air low pressure Condenser hotwell hi level Electric fire pump run HP, IP and LP heater lo level Containment evacuation Channel A, B, C and D fire main pressure available i' RDS isolation valve air pressure low (nitrogen backup not in service)

Radwaste trouble, caused by the following:

Number 1 and Number 2 DWRT High-Low level Number 1 and Number 2 CWRT High-Low level Number 1 and Number 2 WHT High-Low level Chem, waste tank High-Low level Reactor building ventilation system trouble, caused by the fellowing:

Reactor building supply air fans trouble Reactor building High-Low diff Pressure  ;

j Pipeway High-Low diff Pressure BR0781-2035A-BA01

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